Barrerite
is a very rare zeolite (chemical compound found today only in one location in the entire world;
namely two tidal zone mining claims in S.E. Alaska.

Discovered
formerly in Sardinia, Italy, where only a few crystals were
found, the largest was 4-5mm in size. The Italian occurence,
even of this small size, has long since been exhausted.
On the other hand, some of our crystals surpass the 3"
to 4" size but it is extremely rare even at our Alaskan
mines.